1. Field of the Invention
The present invention relates to a hologram film and method for manufacturing the same, and more particularly, to a hologram film having identification information or the like thereon and a method for manufacturing the same.
2. Discussion of the Related Art
Conventionally, in forming multiple duplicates of a master hologram on a recording tape (which is to be wound up on a roller, for example), each duplication has been performed by the steps of contacting the recording film with a master hologram plate and exposing it to laser radiation to induce interference between the incident laser light and diffraction light diffracted from the master plate in the corresponding region of the recording film. As a result, a plurality of duplicated holograms are formed in the recording tape at a fixed interval or at variable intervals. Such a hologram tape is utilized as is, or is cut out to produce separate hologram films each having one or more of duplicated holograms.
To identify or distinguish the duplicated hologram pattern, it is necessary to print identification information or the like, such as a serial number, identification pattern, etc., adjacent each hologram. To print such information on the hologram tape (or each of the separated hologram films), an additional printing process has been required in the conventional method.
Although Japanese Patent Application Laid-Open Publication No. 7-43077 describes a technique for recording additional holographic detection marks for the purpose of using in post-processing, if information specific to the individual hologram pattern, such as a serial number, identification pattern, etc., is to be printed adjacent the corresponding hologram pattern, it was unavoidable to have a separate printing or like process in addition to the hologram duplication process. Further, when such information is optically printed, a separate light source is necessary, as described in Japanese Patent Application No. 3-5555. Thus, the conventional method has drawbacks of a poor throughput and a higher cost due to complexities introduced by the additional step and equipment. Accordingly, it has been long desired to develop a simple and easily controllable method for printing such identification information on a hologram tape (or individual hologram film).